I know next to nothing about buying photos for commercial use, but I know there are a lot of people in that industry here on macrumors, so maybe you can help me. I'm considering buying some photos for use in a shareware application. I know there is something called stock photos, which seems to offer photos for such purposes. I've visited iStockphoto.com and budgetstockphoto.com and I saw some mention of royalty free stock photos. Now I wonder what exactly lies in the term "stock photos" and what does it mean that a photo is royalty free? Are there some licensing terms that I should be particularly aware of? Any recommendations? How much should I expect to pay to use a photo in a shareware application?